fn main() {
    let mut vec:Vec<i32> = Vec::new();
    vec.push(1);
    vec.push(11);
    vec.push(111);
    println!("{:?}", vec);
    println!("{}", vec[0]);
    // 返回的是Option类型
    let vec0 = vec.get(0);
    match vec0 {
        None => {println!("None")}
        Some(zero) => {println!("{}", zero)}
    }

    vec.pop();
    println!("{:?}", vec);

    let v = vec!['a', 'b', 'c'];
    println!("{:?}", v);

    for i in &v {
        println!("{i}")
    }
}
